New research from Stanford shows that mountain lions can drive a trophic cascade even in a small suburban nature preserve. Over five years at Jasper Ridge near San Francisco, rising puma activity lowered deer activity and helped young oak trees and woody plants thrive. The cats also reshaped the smaller predators, with coyotes and bobcats declining, gray foxes rising, and rabbits falling. The findings, published in Ecology and Evolution, show that the ecology of fear is not only a Yellowstone phenomenon. Small preserves connected to large wild areas like the Santa Cruz Mountains can host magnificent ecological effects, which makes protecting top predators and keeping habitats connected more important than ever.